Is your self-test kit really as good as the manufacturer claims?

Is your self-test kit really as good as the manufacturer claims?

There are now many brands of wellness self-testing kits on the market. For your peace-of-mind, all tests sold to the general public through pharmacies and supermarkets in the UK are strictly regulated and registered with MHRA.

Most self-testing kits will accurately determine whether the levels of a particular biomarker are normal or not, just like a hospital lab test. In fact, most of the devices used in self-test kits from reputable manufacturers, will have also been used for years in a hospital setting as well. The problem is that biomarkers found in blood, urine or swabs, will rarely correlate conclusively with the presence or absence of a disease. For example, some people with prostate cancer will have normal levels of prostate specific antigen (PSA), and some people who do not have cancer can have raised levels of PSA for other reasons.

Doctors and scientists will often refer to a test's clinical sensitivity and specificity, which is the probability of a particular biomarker giving a positive result when disease is present, and a negative result when it is not. So, although the lab tests and self-tests can accurately show whether the levels of a biomarker are abnormal, most tests will not tell you with absolute certainty whether you have a specific disease.

Information provided by manufacturers on the accuracy of their tests will usually compare the performance of their self-test with the laboratory equivalent. This is important as it allows doctors to have confidence that the test performs equally well to a test that they may request themselves from a hospital lab. For example, a test that advertises an accuracy of 90% means that in 9 out of 10 times their self-test will give the same readings as a lab test, but it doesn’t mean that the test has a 90% accuracy of detecting disease.

It is important to consider the possibility of false positive or false negative results, and what a result will mean to you before you decide to use a self-testing kit.


SELFCHECK is a range of wellness self-testing kits, assembled in the UK at ISO13485 quality assured laboratories. Professional support is available when help is needed to use the tests or interpret the results with confidence. Find out more about us at

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